Systemic disorder after Fipronil + S-methoprene (Frontline Plus) in dogs

The FDA has received 20 reports of systemic disorder in dogs after Fipronil + S-methoprene. That is 0.7% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

20Reports

75%Marked serious

35%Recovered

0.0%Died or euthanised

–Typical onset

How the animals did

Recovered

6 30%

Recovered with lasting effects

1 5.0%

Still unwell when reported

3 15%

Not known

10 50%

Problems reported at the same time

7 35%

6 30%

5 25%

3 15%

3 15%

3 15%

3 15%

2 10%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fipronil kills fleas and ticks (spot-on).

Products with this combination include Frontline Plus. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Fipronil + S-methoprene cause systemic disorder in dogs?: 20 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Systemic disorder with similar medicines

Systemic disorder after Spinosad (Comfortis) 119 reports · 0.2% of its reports
Systemic disorder after Lufenuron + Milbemycin Oxime (Sentinel) 39 reports · 0.1% of its reports
Systemic disorder after Nitenpyram (Capstar) 31 reports · 0.3% of its reports

All reported side effects of Fipronil + S-methoprene in dogs · Medicines most reported with systemic disorder